Four Points

Milestones
Rafael Nadal, a natural right-hander who learned to hit left-handed as a boy, is the ATP's first lefty year-end No. 1 since John McEnroe in 1984, and when Nadal rocketed to No. 2 in 2005, he was the first lefty to crack the year-end top 10 since Chilean sourpuss Marcelo Rios in 1999. If we assume -- as most studies show -- that southpaws make up roughly 10 percent of the population, they're fairly represented in the ATP's top 100 (12 this week) and the top 20 (Nadal and Fernando Verdasco). The difference from yesteryear is that lefties used to make up a disproportionate percentage of the top 10, spiking in 1975, when it was a 50-50 split (Jimmy Connors, Guillermo Vilas, Manuel Orantes, Roscoe Tanner and Rod Laver finished the season ranked Nos. 1, 2, 5, 9 and 10, respectively). There were almost always two left-handed players in the year-end top 10 throughout the '80s and into the mid-'90s -- as the Connors-Vilas-John McEnroe troika gave way to players like Goran Ivanisevic, Thomas Muster, Greg Rusedski and Rios -- but their ranks have thinned definitively since.

Over on the distaff side
No. 11 Patty Schnyder of Switzerland continues her lonely tenure as the only lefty of note in the WTA's top echelons. Two of the best players of all time -- Martina Navratilova and Monica Seles -- were lefties, but there's a pretty steep historical drop-off after that. Other left-handers on the radar screen today are No. 26 Sybille Bammer of Austria, No. 52 Casey Dellacqua of Australia and No. 66 Lucie Safarova of the Czech Republic. While two of the men's top four doubles teams feature lefty-righty combinations (Bob and Mike Bryan, Daniel Nestor and Nenad Zimonjic), the top four women's teams are an all-righty gang.

Unconventional wisdom
The geometry of the game has long been thought to give left-handers an edge, provided they can exploit it. A lefty's cross-court forehand goes to a righty's ostensibly weaker backhand. While the opposite is also true, right-handers don't have as much practice going for a winner that way in pressure situations, since they face left-handers less often. The lefty's serve pulls the righty out wide in the ad court, where most critical points are played. Finally, lefties bring different vision to the court and put exotic spins on their shots.

Left behind
Is there a logical reason behind the decline of lefties in the men's top ranks, and their relative paucity among the women?

ESPN commentator and former pro Mary Carillo, an admittedly biased lefty, echoed many experts when she said that players are far more skilled off both wings these days, aided by lighter rackets and strings that impart more power and control. "I honestly think lefties lost a considerable amount of their natural advantage when the two-handed backhand came into widespread use,'' she said. "And the return game is so much more of a weapon now.''

Former top-10 player Eliot Teltscher, who came of age in the era of great lefties, tends to view the current -- and past -- percentages as more cyclical and coincidental. As he put it, all left-handers are not created equal, and sometimes the side they play from is ancillary to their success. "Some lefties play with the style of righties,'' he said, citing Connors, who hit the ball hard and flat, as a prime example. "No one lost to Jimmy because he served them off the court. He rushed you and had an unbelievable return.'' McEnroe and Navratilova were rarities in that they truly played a distinctive style related to their lefty touch, Teltscher added.

Carillo doesn't disagree with that point. "Vilas just happened to be a lefty,'' she said. "With John and Martina, it was organic.'' She characterized Nadal as a bit of a hybrid who lacks a pure lefty serve, but "plays like a lefty once he's into the point,'' Carillo said. "If he were a righty, his game would be a lot the same. But he finds angles I've never seen. Part of that is that he's strong enough to create them.''

Bonnie D. Ford covers tennis and Olympic sports for ESPN.com. She can be reached at bonniedford@aol.com.